(A–A’’’) Maximum intensity projection of a confocal image of HCR RNA-FISH for foxi3b
(A’), trpv6
(A’’), ceacam1
(A’’’), and merged signals (A) in the head of a 5 dpf wild-type larva; dorsal view, anterior to the top. Scale bar: 50 μm. White arrowhead marks an example of an olfactory ionocyte in the posterior-lateral region of the olfactory pit with expression of foxi3b. White arrow marks an example neuromast ionocyte with expression of all three selected genes. Abbreviations: OE; olfactory epithelium, Nm; neuromast. (B) Numbers of foxi3b+ ionocytes per olfactory pit in 5 dpf larvae raised in 0.5× E2 medium, of which also express trpv6. Connecting lines indicate the same olfactory pit. (C–C’’) Confocal image of HCR RNA-FISH signals for trpv6
(C’), ceacam1
(C’’), and merged signals (C) in the olfactory epithelium of a 5 dpf wild-type larva; dorsal view, anterior to the top, lateral to the right. Scale bar: 20 μm. Magenta and cyan arrowheads mark an example pair of ionocytes, with the magenta arrowhead marking a strong trpv6 and weak foxi3b-expressing cell, and the cyan arrowhead marking a ceacam1+ cell. Yellow arrowhead marks an example solitary ionocyte, which has strong expression of foxi3b and weak expression of trpv6. (D–D’’) HCR RNA-FISH for foxi3a (yellow) and trpv6 (magenta), combined with the Notch reporter tp1bglobin:EGFP (cyan) and DAPI stain (grey). (E–E’’) HCR RNA-FISH for slc9a3.2 (yellow) and trpv6 (magenta) with DAPI stain (grey). (F–F’’) HCR RNA-FISH for slc4a1b (magenta) combined with the Notch reporter tp1bglobin:EGFP (cyan) and DAPI stain (grey). (G–G’’) Maximum intensity projection of a HCR RNA-FISH for slc12a10.2 (yellow) and foxi3b (magenta) with DAPI stain (grey) shows solitary, NCC-like ionocytes in the olfactory epithelium. (H–H’’) HCR RNA-FISH for slc12a10.2 (yellow) and chrd (magenta) with DAPI stain (grey). (I–I’’) HCR RNA-FISH for slc12a10.2 (yellow) and hepacam2 (magenta) with DAPI stain (grey).